Plural component materials are typically applied using a spray system. Typical examples of plural components include but are not limited to epoxies, paints, urethane- and polyurea-based coatings, and urethane-based pour and spray foams. Plural component materials typically include a first fluid component and a second fluid component. By way of example only, the first fluid component and the second fluid component may respectively comprise a resin and a hardener, a resin and an activator, or an amine and an isocyanate.
As shown in FIGS. 1-3, a conventional spray system, such as spray systems 10 and 10′, typically includes a pair of storage tanks 20a and 20b, a proportioner 30, and a spray gun 40 that includes a spray gun manifold 50. As shown in FIGS. 1-3, each of the pair of storage tanks 20a, 20b is connected to the proportioner 30 via a respective one of a pair of proportioner supply lines 22a, 22b that allow the fluid components to flow separately from the respective storage tank 20a, 20b to the proportioner 30. Each storage tank 20a, 20b also includes a feed pump 26a, 26b configured to pump the fluid components from their respective storage tank 20a, 20b to the proportioner 30 through the corresponding proportioner supply line 22a, 22b. In addition, in the illustrated systems 10, 10′, the proportioner 30 is connected to the spray gun 40 via the spray gun manifold 50 with a heated hose 60, which allows the fluid components to flow separately from the proportioner 30 through the spray gun manifold 50 and, ultimately, to the spray gun 40, where the individual fluid components are mixed in an inner mixing chamber in the spray gun and delivered through the nozzle of the spray gun 40. The heated hose 60 typically comprises a pair of heated gun supply hoses 62a, 62b connected to a corresponding pair of heated whip hoses 64a, 64b via a fluid temperature sensor 66. As shown in FIGS. 2 and 3, the fluid temperature sensor 66 and adjacent sections of heated gun supply hoses 62a, 62b and heated whip hoses 64a, 64b are exposed for illustration purposes. The fluid temperature sensor 66 and adjacent hoses are typically wrapped in thermal tape during normal operation of spray system 10, 10′. The illustrated spray systems 10 and 10′ also include a gun air supply hose 51 configured to supply pressurized air from the proportioner 30 to the spray gun 50.
Spray system 10 shown in FIGS. 1 and 2 also includes a pair of circulation lines 24a, 24b between the proportioner 30 and a respective storage tank 20a, 20b. The proportioner 30 includes an operational setting configured to separately circulate the fluid components through the proportioner 30 and back into their respective storage tank 20a, 20b. While such an operational setting is active, the fluid components flow separately through the respective fluid supply line 22a, 22b, continue through the proportioner 30 and return to their respective storage tanks 20a, 20b via the circulation lines 24a, 24b. Spray system 10′ shown in FIG. 3 is identical to spray system 10 shown in FIGS. 1 and 2, except that spray system 10′ does not include circulation lines 24a, 24b. In other words, spray system 10 represents a typical spray system with circulation, while spray system 10′ represents a typical spray system without circulation.
FIGS. 4-8 depict two types of conventional spray guns 140, 240 and their corresponding spray gun manifolds 150, 250. Spray gun 40 and spray gun manifold 50 shown in FIGS. 1-3 may comprise any type of suitable spray gun and spray gun manifold. For example, spray gun 50 may comprise a spray gun configured to work in conjunction with a spray gun manifold comprising a single junction block, such as junction block spray gun 140 and junction block spray gun manifold 150 shown in FIGS. 4-5. One commercial example of this type of junction block spray gun is the Fusion Air Purge spray gun made by Graco Inc. Junction block spray gun 140 includes an air hose coupling 157 configured to allow a user to attach an air hose, such as gun air supply hose 51, to the junction block spray gun 140 in order to provide pressurized air to the junction block spray gun 140. In another example, spray gun 50 may comprise a spray gun configured to work in conjunction with a spray gun manifold comprising two individual side blocks, such as side block spray gun 240 and side block spray gun manifold 250 shown in FIGS. 6-8.
As shown, the junction block spray gun manifold 150 comprises a single junction block 152 that includes a first hose coupling 154a and a second hose coupling 154b. In FIG. 5, whip hose 64a is connected to first hose coupling 154a and whip hose 64b is connected to second hose coupling 154b. Junction block 152 also includes a first manifold valve 156a associated with the first hose coupling 154a and a second manifold valve 156b associated with second hose coupling 154b. First manifold valve 156a may be configured to selectively open and close to either allow the respective fluid component to flow from whip hose 64a through junction block 152 and into the inner mixing chamber of junction block spray gun 140 or prevent delivery of the fluid component into the inner mixing chamber of junction block spray gun 140. Similarly, second manifold valve 156b may be configured to selectively open and close to either allow the respective fluid component to flow from whip hose 64b through junction block 152 and into the inner mixing chamber of the junction block spray gun 140 or prevent delivery of the fluid component into the inner mixing chamber of the junction block spray gun 140.
In this embodiment, first hose coupling 154a comprises a female coupling 155a configured to receive a corresponding male coupling 65a on the end of one of the pair of whip hoses 64a, 64b. Similarly, second hose coupling 154b comprises a female coupling 155b configured to receive a corresponding male coupling 65b on the end of the other one of the pair of whip hoses 64a, 64b. As shown in FIG. 5, junction block 152 further comprises a pair of gun couplings 158a, 158b configured to connect junction block 152 to the junction block spray gun 140 and provide communication between the junction block spray gun manifold 150 and the inner mixing chamber of the junction block spray gun 140. Each gun coupling 158a, 158b may have a smooth metal finish and a fluid port that is centered within the respective gun coupling 158a, 158b. The fluid port in junction block spray gun 140 that each gun coupling 158a, 158b is connected to may include an o-ring to provide an adequate seal between junction block 152 and junction block spray gun 140. The junction block 152 may be attached to the junction block spray gun 140 using any suitable fastener 160, including but not limited to a conventional fastener, such as the pin shown in FIG. 5, or any other fastening means or method that provides an adequate connection between the junction block 152 and the junction block spray gun 140.
FIGS. 6-8 depict an alternate type of spray gun and gun manifold. Specifically, as shown in FIGS. 6-8, side block spray gun 240 is configured to work in conjunction with a side block spray gun manifold 250 comprising two individual side blocks 252a, 252b. One commercial example of this type of side block spray gun is the Probler P2 spray gun made by Graco Inc. Side block spray gun 240 includes an air hose coupling 257 configured to allow a user to attach an air hose, such as gun air supply hose 51, to the side block spray gun 240 in order to provide pressurized air to the side block spray gun 240.
In the illustrated embodiment, the side blocks 252a, 252b are configured to mount onto either side of the side block spray gun 240 and each side block 252a, 252b includes a union fitting 254a, 254b. Each side block 252a, 252b also includes a manifold valve 256a, 256b associated with the respective union fitting 254a, 254b. Each manifold valve 256a, 256b may be configured to selectively open and close to either allow the respective fluid component to flow from the connected hose, such as whip hose 64a, 64b, through the respective side block 252a, 252b and into the inner mixing chamber of the side block spray gun 240 or prevent delivery of the fluid component into the inner mixing chamber of the side block spray gun 240. In this embodiment, each side block 252a, 252b further comprises a female hose coupling 255a, 255b configured to receive a corresponding male hose coupling, such as male coupling 65a, 65b shown in FIG. 5, on the end of one of the pair of whip hoses 64a, 64b. 
Each side block 252a, 252b also includes a gun coupling configured to connect the respective side block 252a, 252b to the side block spray gun 240 and provide communication between each side block 252a, 252b and the inner mixing chamber of the side block spray gun 240. Gun coupling 258b on side block 252b is illustrated in FIG. 8. The corresponding gun coupling on side block 252a is not shown, but it is substantially identical to gun coupling 258b. As illustrated in FIG. 8, side blocks 252a, 252b are attached to side block spray gun 240 using one or more suitable fasteners 260, including but not limited to a conventional fastener, such as a screw or pin, or any other fastening means or method that provides an adequate connection between the side blocks 252a, 252b and the side block spray gun 240.
In some circumstances, it may be desirable to recirculate the individual fluid components through at least a portion of the system without mixing and discharging them through the spray gun. For example, circulating the fluid components may help prevent debris from clogging up hoses, ports, and couplings located throughout the spray system. Recirculating the fluid components may also help maintain or improve the quality of the fluid components by causing fillers contained within the fluid components to be re-suspended within the fluid instead of settling within the storage tanks, the proportioner, or the hoses. In addition, circulating the individual fluid components may also allow the user to preheat the fluid components before they are mixed and sprayed, which may result in an improved application. Recirculating fluid components through the system may be done as a part of the regular maintenance for the components of the spray system in order to maintain or improve the performance and lifespan of the various components.
As described above, some spray systems, such as spray system 10 shown in FIG. 2, include circulation lines 24a, 24b between the storage tanks 20a, 20b and the proportioner 30 that allow the user to recirculate fluid components from the storage tanks 20a, 20b, through the proportioner 30 and back into the storage tanks 20a, 20b. While helpful to an extent, this limited recirculation does not provide the same benefits as recirculating the fluid components through the entire system. Specifically, when the recirculation is limited to the circuit between the storage tanks 20a, 20b and the proportioner 30, any fluid components located in the system components downstream of the proportioner (e.g., heated hose 60, whip hoses 64a, 64b, and spray gun manifold 50) are not recirculated. As a result, any such fluid components are not preheated, the fillers are not re-suspended in those fluid components, and debris is not removed from the system components and the associated couplings and ports.
In some systems, heated hose 60 may comprise about 400 or more feet of hose, so there can be a substantial amount of fluid components located within the heated hose 60. Therefore, it may be beneficial to recirculate the fluid components throughout the entire spray system. One way to recirculate the fluid components throughout the entire spray system is to use a recirculation block. In its simplest form, a recirculation block may include an entry port (or set of entry ports) configured to connect to spray gun manifold 50 to receive fluid components and an exit port (or set of exit ports) configured to connect to one or more return hoses that lead back to storage tanks 20a, 20b, such as circulation lines 24a, 24b. 
FIG. 9 depicts spray system 310, which is identical to spray system 10 of FIG. 1, except that spray gun 40 has been replaced with a recirculation block 300. Incorporating recirculation block 300 into spray system 310 results in a complete circuit that allows the user to recirculate the fluid components through the entire spray system 310. In the illustrated embodiment, the fluid components flow from storage tanks 20a, 20b to proportioner 30 through proportioner supply lines 22a, 22b. After passing through proportioner 30, the fluid components then flow to spray gun manifold 50 via heated hose 60, fluid temperature sensor 66 and whip hoses 64a, 64b. Finally, the fluid components flow from spray gun manifold 50, through recirculation block 300 and return to storage tanks 20a, 20b via circulation lines 24a, 24b, thereby completing the circuit. The arrows in FIG. 9 indicate the direction of the flow of fluid components through spray system 310.
FIG. 10 depicts an example of a prior art recirculation block 400, such as a Part 15B853 Circulation Manifold made by Graco Inc., which is part of a 246362 Circulation Manifold Kit also made by Graco Inc. Recirculation block 400 is configured to be used in conjunction with a junction block spray gun and a corresponding spray gun manifold comprising a single junction block, such as junction block spray gun 140 and junction block spray gun manifold 150 shown in FIGS. 4 and 5 and described above. In the illustrated embodiment, recirculation block 400 only includes a single pair of entry ports 402a, 402b that are configured to connect with a spray gun manifold comprising a single junction block, such as junction block spray gun manifold 150. Specifically, as shown, entry ports 402a, 402b are configured to connect to gun couplings 158a, 158b of junction block spray gun manifold 150 to allow fluid components to flow from whip hoses 64a, 64b through junction block spray gun manifold 150 and into recirculation block 400. As shown in FIG. 10, recirculation block 400 further comprises a pair of exit ports that are configured to connect with a pair of return hoses, such as circulation lines 24a, 24b. By way of example only, the return hoses may lead back to the tank of origin, such as storage tanks 20a, 20b, or to an independent tank for separate storage. Recirculation block 400 also includes a plurality of mounting apertures 401 that are configured to allow recirculation block 400 to be attached to a mounting surface or structure. Mounting apertures 401 are not in fluid communication with entry ports 402a, 402b or the pair of exit ports.
It will be appreciated that recirculation block 400 is not configured to be used in conjunction with a side block spray gun and a corresponding spray gun manifold comprising a pair of side blocks, such as side block spray gun 240 and side block spray gun manifold 250. Accordingly, it may be beneficial to provide a single recirculation block that is configured to be used with both a junction block spray gun and a side block spray gun and their respective spray gun manifolds.
While a variety of recirculation blocks have been made and used, it is believed that no one prior to the inventor(s) has made or used an invention as described herein.
The drawings are not intended to be limiting in any way, and it is contemplated that various embodiments of the invention may be carried out in a variety of other ways, including those not necessarily depicted in the drawings. The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention, and together with the description serve to explain the principles of the invention; it being understood, however, that this invention is not limited to the precise arrangements shown.